1. Field of the Invention
The present invention relates generally to mobile communication devices and network selection techniques employed thereby, and more particularly to network selection techniques based on quality of service (QoS) criteria associated with software applications on a mobile device.
2. Description of the Related Art
The 3rd Generation Partnership Project (3GPP2) Technical Specification Group (TSG)-P (data services and applications) defines four types of CDMA2000 airlink traffic classes having associated Quality of Service (QoS) attributes: (1) Conversational traffic class; (2) Streaming traffic class; (3) Interactive traffic class; and (4) Background traffic class. Conversational traffic class applications correspond to traditional voice applications which are usually two-way and sensitive to delay, delay variation, and data loss. Streaming traffic class applications are usually one-way and less sensitive to delay and data loss, but are sensitive to delay variations and may require a high bandwidth. A good example of a streaming traffic class application is a video player application. Interactive traffic class applications are two-way “bursty” types of applications. These applications can tolerate moderate delay and data loss and have variable bandwidth requirements. On-line video game and web-surfing (browser) applications are good examples of the interactive traffic class. Finally, background traffic class applications are those which are highly tolerant of delay and data loss and may have variable bandwidth requirements. Examples of these applications include e-mail and file transfer applications.
Due to historical reasons, conventional network selection methods are based largely on conversational traffic class applications (i.e. voice). The IS-683b standard, for example, defines a Preferred Roaming List (PRL) for system selection and acquisition. The PRL includes two tables: the system table and the acquisition table. The system table contains records, each of which identifies a network by its System Identification (SID) and Network Identification (NID). For each record, there is an indicator of whether the system is preferred or negative, the roaming status that should be indicated by the mobile device, the relative priority of the system, and its geographic region. Each record also contains an acquisition index which indicates a record in the acquisition table to be used. The acquisition record provides the band and frequencies that are to be used when attempting to acquire the system.
The IS-683 system selection algorithm works well for conversational traffic class applications (i.e. voice). Problems may arise, however, when different types of data applications are utilized by the mobile device. If a mobile device is operating in home network coverage, it is not guaranteed that its application requirements will be be met. For example, a streaming traffic class application which requires a high bandwidth will not work if the mobile device's current network provides only a low bandwidth. As another example, a mobile device under weak signal coverage (typically resulting in high packet data loss) may serve background traffic class applications well but not interactive traffic class applications (e.g. an interactive video game). Furthermore, two different carriers may have a voice roaming agreement but not a data roaming agreement. In this case, a non-home foreign network suitable for voice may not be suitable for a data application at all. Even if a data roaming agreement existed between these carriers, the home carrier may still prohibit mobile devices from roaming onto the foreign network in cities where it provides system coverage itself. When a data call is attempted on such a foreign network, authentication failures typically occur as a result. This wastes network resources and battery life and gives the end user a poor service experience.
Accordingly, there is a need for methods and apparatus for selecting a wireless network for communication that overcomes the deficiencies of existing techniques.